Disclosed are methods and nutritional compositions for the promotion of muscle protein synthesis or the control of tumor-induced weight loss, such as cancer cachexia.
Cachexia is a condition of severe malnutrition and negative nitrogen balance characterized by anorexia (i.e. a lack or severe loss of appetite), weight loss, and muscle atrophy. The physiological, metabolic, and behavioral changes in cachexia are associated with patient complaints of weakness, fatigue, gastrointestinal distress, sleep/wake disturbances, pain, listlessness, shortness of breath, lethargy, depression, malaise and the fear of being burdensome on family and friends. Although cachexia has been classically associated with chronic infections and malignant conditions, it has also been identified in patients after extensive traumatic injury and sepsis and in aging persons with failure to thrive syndrome.
Loss of lean body mass associated with cancer cachexia not only weakens the individual and makes activities of daily living difficult, but can weaken the patient to the point that they do not have the strength to undergo chemo- and/or radiation therapy.
Two main components contribute to cancer cachexia—a loss of appetite and a metabolic response to stress that causes a preferential loss of muscle at a rate greater than would be expected from the lack of nutritional intake alone. Consequently, a nutritional supplement to ameliorate the rate of loss of muscle mass in patients with cancer would have an important clinical impact.